This invention relates to the measurement of isotope ratios and/or isotopic abundances using Raman scattering.
Isotope ratio measurements have become increasingly important in chemistry, biology, and medicine in recent years. This is primarily due to the increased availablity of enriched isotopes and labeled compounds. Furthermore, the availiability of these isotopes is expected to increase even more as refinements are made in the techniques of laser isotope separation. As a result, isotope ratio measurements will become even more common in the near future.
When dealing with radioactive isotopes little difficulty is encountered in making the isotope ratio measurements. However, when dealing with stable isotopes (which are preferable to radioactive isotopes in many studies for safety reasons) th situation is different. At present, mass spectrometry is the only accurate method for making stable isotope ratio measurements. This technique is slow, requiring minutes for even a crude measurement, and it consumes the sample. The extremely long time required for each measurement severely limits the number of samples which can be analyzed in a reasonable length of time. As a consequence many important studies using stable isotopes as tracers are not feasible at this time.
Therefore, it it highly desireable to have a technique for measuring stable isotope ratios which is at least an order of magnitude faster than mass spectrometry and which, if possible, does not consume the sample.